The present invention relates to an optical element holding apparatus for holding an optical element such as a lens and a mirror. The present invention also relates to a barrel including at least one optical element. The present invention further relates to an exposure apparatus used when manufacturing a device such as a semiconductor device, a liquid crystal display device, and a thin-film magnetic head, and to a manufacturing method for a device.
An optical system for this type of exposure apparatus includes optical elements such as a lens and a mirror. In this type of exposure apparatus, each optical element may be distorted when assembling, storing, transporting, or operating the optical system due to temperature changes and external impacts. Such distortion must be minimized or eliminated.
In this regard, the optical systems of the exposure apparatus have a projection optical system that includes optical elements (e.g., a lens) generally accommodated in a barrel by means of a holding apparatus. This holding apparatus includes a lens cell, and the lens cell is designed to prevent vibrations that are produced when assembling the projection optical system (e.g., impact applied to the barrel and transmitted to the lens) and to offset the difference in linear expansion coefficient between the lens and the lens cell caused by temperature changes.
Circuit patterns of semiconductor devices have become further miniaturized due to strict demands for higher integration. Thus, in a semiconductor device manufacturing exposure apparatus, it is required that the exposure accuracy be further improved and that the resolution be further increased. This has increased the significance of technology for holding an optical surface of an optical element in a satisfactory state.
As such a holding apparatus, a holding apparatus including a cantilever bent portion that is formed in the lens cell has been proposed. For example, the holding apparatus has three seating positions, to which a lens is adhered, on the cantilever bent portion (see U.S. Pat. No. 4,733,945). In this conventional structure, the cantilever bent portion absorbs expansion and contraction of the lens cell caused by temperature changes so that mechanical stress does not distort the lens.